Mobile radio network node and method for estimating a capacity of a link in a radio communications network

ABSTRACT

A mobile radio network node sends echo request messages to a defined end-point node via a link in a radio communications network. Based on return messages generated in response to the echo request messages a capacity of the link is estimated. The echo request messages contain standardized first and second test messages, where the first test message includes a first amount of data, and the second test message includes a second amount of data exceeding the first amount of data. The capacity of a link in terms of an amount of data communicated per unit time is estimated based on an amount of residue data corresponding to a difference between the second and first amounts of data, and a difference between first and second time intervals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage application (filed under 35 U.S.C.§ 371) of International Application No. PCT/SE2018/050055, filed Jan.24, 2018, which, in turn, claims priority to Swedish Application No.1750211-3 filed Feb. 27, 2017; the contents of each of which are herebyincorporated by reference in their entirety.

TECHNICAL FIELD

The invention relates to a mobile radio network node for use in a radiocommunications network and a method implemented in a mobile radionetwork node. The invention also relates to a computer program and anon-volatile data carrier.

BACKGROUND

The concept of throughput is a fundamental metric of anytelecommunications network. Especially in computer networks, it isimportant to measure throughput because this benchmarks the network andsets the user expectations on the network capacity. Typically, however,the user-available throughput fluctuates. This is particularly true inradio networks with a shared medium for example WiFi networks (i.e.wireless networks implementing any of the standards in the IEEE 802.11family) and LTE (Long-Term Evolution) networks, which are two of themost popular access networks to the Internet today.

Normally, the throughput measurement schemes involve sending maximumtraffic between two network nodes for a certain amount of time. A numberof different tools are available, which implement such a strategy. Themeasurement can be conducted using different traffic protocols orprofiles. Below follows a few examples of known solutions for capacitymeasurement.

US 2007/0025263 discloses methods and systems for estimating availablebandwidth on an internet access network. The method involves: (a)transmitting one or more Internet Control Message Protocol (ICMP) echorequest packets to a device residing on the network at a first bit rate;(b) receiving one or more ICMP echo reply packets corresponding to theone or more ICMP echo request packets responsive to step (a); and (c)determining a second bit rate for the one or more ICMP echo replypackets. If the second bit rate is less than the first bit rate,available bandwidth is estimated based on the second bit rate. If thesecond bit rate is not less than the first bit rate, steps (a), (b) and(c) are repeated. The first bit rate is increased for each iteration,until the second bit rate is less than the first bit rate, and thenavailable bandwidth is estimated based on the second bit rate.

US 2004/0001511 describes a method of estimating bandwidth capacity,available bandwidth and utilization along a path in an IP network. Here,ICMP time-stamp requests are sent from a source host on the edge orinside the network to all routers on the end-to-end path to a desireddestination. Differences between time-stamp values are used asindicators of QoS service at each router. The collected measurements arethen processed at the sending host to infer QoS parameters in terms ofpath capacity in bits/sec, available bandwidth in bits/sec, individuallink utilization and congestion at each router. These parameters can becombined to infer the QoS service in terms of bandwidth on theend-to-end path.

CN 102045219 shows a method for high-efficiency single-end availablebandwidth measurement, which contains the following steps: atransmitting end transmits a specific probe packet train to adestination node; the transmitting end calculates a series of round triptime (RTT) delay values in accordance with a series of ICMP packetsreturned by the destination node, and determines the time when the roundtrip time delay starts to remain constant; and the transmitting endcalculates the average transmission rate of the packet train within thetime period from the time when the packet train starts to be transmittedto the time when the round trip time delay starts to remain constant,and uses the average transmission rate as the measured value of theavailable bandwidth of the path. Single-end available bandwidthmeasurement is provided based on the probe packet train, and theavailable bandwidth value can be measured by only transmitting the probepacket train once. Thus, high measurement accuracy, high convergencespeed, low invasion degree and high robustness are attained.

U.S. Pat. No. 7,573,886 describes a method of determining effectivebandwidth, where a first packet size is selected, and then a firstpacket is sent having the first packet size from a first node to asecond node. A confirmation that the first packet was received in thesecond node is received. A transfer time of the first packet isrecorded. A second packet size is selected and a second packet havingthe second packet size is sent from the first node to the second node. Aconfirmation that the second packet was received in the second node isreceived and a transfer time of the second packet is recorded. Aneffective bandwidth between the first node and the second node iscalculated and the effective bandwidth can be output.

US 2010/00142395 discloses a band measurement method for measuring aband available for communication with a target device connected via anetwork. The method includes: transmitting a first request having afirst data size and requesting a response having a fixed size to thetarget device via the network; determining a first time between thetransmitting of the first request and the receipt of the response uponreceipt of the response; transmitting a second request having a seconddata size and requesting a response having the fixed size to the targetdevice via the network; determining a second time between transmittingof the second request and the receipt of the response upon receipt ofthe response; and calculating a first communication band available fortransmitting data to the target device by dividing the differencebetween the first and second data sizes by the difference between thefirst and second times.

The existing solutions are however problematic for various reasons. Forexample, according to some of the solutions, during the test, thenetwork is flooded with test traffic. This, in turn, renders the networktemporarily unusable for the normal traffic. Therefore, no long-termthroughput measurements can be carried out in production networks duringoperation. Further, the end-points may need to install particularsoftware to generate and/or analyze the test traffic. This substantiallylimits the number of end-points de facto available. According to otherknown solutions, the network is less congested by the test traffic.Nevertheless, these solutions provide relatively inaccurate measures ofthe actual throughput, especially for wireless networks.

SUMMARY

One object of the present invention is therefore to mitigate the aboveproblems and thus offer reliable evaluation of a network's capacitywithout flooding the network with high amounts of test traffic.

A further object of the invention is to enable dynamic throughputmeasurements, which can form a basis for positioning a wireless routerand/or choosing an appropriate radio channel in a wireless network.

According to one aspect of the invention, these objects are achieved bya mobile radio network node for estimating the capacity of a radiocommunications network. The mobile radio network node includes: a radiointerface, a processor and a memory. The radio interface is configuredto exchange data wirelessly via the radio communications network. Thememory contains instructions executable by the processor, whereby themobile radio network node is operative to send echo request messages viaa link in the radio communications network to a defined end-point node.The processor executable instructions in the memory further render themobile radio network node operative to estimate the capacity of the linkin the radio communications network based on return messages generatedin response to the echo request messages. The return messages originatefrom the defined end-point node. In particular, the echo requestmessages comprise first and second test messages. Here, the first testmessage includes a first amount of data, and the second test messageincludes a second amount of data exceeding the first amount of data.Additionally, the instructions executable by the processor are furtherconfigured to render the mobile radio network node operative to performa measuring step. In this step, the capacity of the link in the radiocommunications network is estimated based on (i) an amount of residuedata corresponding to a difference between the second and first amountsof data, and (ii) a difference between first and second time intervals.The first time interval is the time elapsed between sending the firsttest message and receiving a first return message in response thereto,and the second time interval is the time elapsed between sending thesecond test message and receiving a second return message responsethereto.

The proposed mobile radio network node is advantageous because it allowsfrequently repeated measurements with only marginal influence on thenetwork being analyzed. Moreover, the first and second test messages maybe represented by standardized messages included in the most commonlyused communication protocols. This, in turn, avoids the need ofinstalling any dedicated software in the defined end-point node.

According to one embodiment of this aspect of the invention, the firstand second amounts of data included in the first and second testmessages respectively are such that the residue data contains bothpayload data and overhead data generated by a communication protocolused in the radio communications network. As a result, any negativeeffects on the throughput caused by various overhead factors are dulytaken into consideration, and a realistic throughput measure can beattained.

For example, the first test message may contain a minimal amount ofpayload data and the second test message may contain an amount ofpayload data that exceeds one maximum transmission unit in the radiocommunications network.

This is advantageous because by studying the first test message it isstraightforward to deduct the amount of overhead added to each messageby the radio network in question, and the second test message provides abasis for studying the effects of frame aggregation in the network.Hence, the network capacity can be estimated relatively accurately.

According to another embodiment of this aspect of the invention, theinstructions executable by the processor are specifically configured torender the mobile radio network node operative to send the second testmessage as soon after sending the first test message as is possible withrespect to a communication protocol used in the radio communicationsnetwork. Namely, thereby, the network conditions experienced by the twomessages are as similar as possible. This, in turn, vouches for accuracywhen for example using a round-trip time related to the first message tonormalize a round-trip time related to the second message.

According to another embodiment of this aspect of the invention, theinstructions executable by the processor are further configured torender the mobile radio network node operative to: repeat the measuringstep a number of times, say five times; and perform an averagingoperation over said number of times to obtain the estimated capacity ofthe link. Since the proposed measurements only have a very small effecton the other traffic in the network, this causes marginal loads whileimproving the reliability of measurement result.

According to yet another embodiment of this aspect of the invention, themeasuring step involves determining an estimated average throughput,and/or determining an estimated maximum throughput of the link.

For example, the estimated average throughput can be determined as: twotimes the amount of residue data divided by a denominator in the form ofan average round-trip time for the second test message and the secondreturn message over said number of times minus a shortest round-triptime for the first test message and the first return message over saidnumber of times.

Similarly, the estimated maximum throughput can be determined as: twotimes the amount of residue data divided by a denominator in the form ofa shortest round-trip time for the second test message and the secondreturn message during said number of times minus the shortest round-triptime for the first test message and the first return message over saidnumber of times.

According to still another embodiment of this aspect of the invention,the instructions executable by the processor are configured to renderthe mobile radio network node operative to repeat the measuring step insuch a manner that the second amount of data included in the second testmessage is varied between different transmissions of the second testmessage over said number of times. For example, in an initialtransmission, the second test message may contain a predefined maximumamount of data; and if no second return message is received in responseto the second test message, in at least one transmission subsequent tothe initial transmission, the second test message may contain an amountof data being less than the predefined maximum amount of data. Thus, inaddition to measuring the capacity, it can be checked how large messagesthat can be passed through the link.

According to a further embodiment of this aspect of the invention, theradio communications network is configured to communicate data accordingto the ICMP, the Transmission Control Protocol (TCP), the Real-TimeTransport Protocol (RTP), the User Datagram Protocol (UDP) and/or theIETF RFC 862 Echo Protocol. The instructions executable by the processorare configured to render the mobile radio network node operative togenerate each of the first and second test messages as a respectivestandardized message in ICMP, TCP RTP, UDP and IETF RFC 862 EchoProtocol respectively, i.e. messages implementing ping functionalityunder the protocol in question. Consequently, no dedicated software isrequired in the defined end-point node to employ the proposed procedure.

According to another aspect of the invention, the above objects areachieved by a method performed in a mobile radio network node forestimating a capacity of a radio communications network. The methodinvolves sending echo request messages via a link in the radiocommunications network to a defined end-point node, and estimating thecapacity of the link based on return messages generated in response tothe echo request messages, which return messages originate from thedefined end-point node. Specifically, the echo request messages containfirst and second test messages, where the first test message includes afirst amount of data, and the second test message includes a secondamount of data exceeding the first amount of data. The method involves ameasuring step. Here, the capacity of the link is estimated based on (i)an amount of residue data corresponding to a difference between thesecond and first amounts of data, and (ii) a difference between firstand second time intervals. The first time interval is the time elapsedbetween sending the first test message and receiving a first returnmessage in response thereto. Analogously, the second time interval isthe time elapsed between sending the second test message and receiving asecond return message response thereto. The advantages of this method,as well as the preferred embodiments thereof, are apparent from thediscussion above with reference to the proposed mobile radio networknode.

According to a further aspect of the invention the objects are achievedby a computer program containing instructions which, when executed on atleast one processor, cause the at least one processor to carry out theabove-described method

According to another aspect of the invention the objects are achieved bya non-volatile data carrier containing such a computer program.

Further advantages, beneficial features and applications of the presentinvention will be apparent from the following description and thedependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now to be explained more closely by means of preferredembodiments, which are disclosed as examples, and with reference to theattached drawings.

FIG. 1 schematically shows a first embodiment of the invention, whereina mobile radio network node estimates the capacity of a link to anend-point node in a radio communications network;

FIG. 2 schematically shows a second embodiment of the invention, whereina mobile radio network node estimates the capacity of a link to anend-point node in a radio communications network;

FIG. 3 shows a block diagram over a mobile radio network node accordingto one embodiment of the invention; and

FIG. 4 illustrates, by means of a flow diagram, a method according toone embodiment of the invention.

DETAILED DESCRIPTION

A first embodiment of the invention is represented in FIG. 1. Here, wesee a schematic representation of a mobile radio network node UE, forexample in the form of a user equipment implementing a mobile/cellulartelephone, a laptop computer or any other device equipped with a radiointerface towards a radio communications network NW.

In any case, the mobile radio network node UE is configured to send echorequest messages via a link L in the radio communications network NW toa first defined end-point node EPN1. Based on return messages generatedin response to the echo request messages, the mobile radio network nodeUE is further configured to estimate the capacity of the link L in termsof throughput (i.e. an amount of data per unit time transmittable viathe link L).

More precisely, according to the invention, the echo request messagescontain first and second test messages M1 and M2 respectively. The firsttest message M1 includes a first amount of data, and the second testmessage M2 includes a second amount of data exceeding the first amountof data.

Preferably, the first test message M1 contains a minimal amount ofpayload data, in other words no payload data at all. I.e. the first testmessage M1 may merely be an empty message with the headers normallyapplied by the communications protocol that is used in the network NW.Typically, in a network NW carrying Internet traffic the communicationsprotocol is the ICMP, the TCP, the RTP and/or the UDP, and the firsttest message M1 is a message implementing a standardized pingfunctionality. This means that the first test message M1 may be an ICMPEcho Request message, or equivalent standardized message in TCP RTP, UDPand IETF RFC 862 Echo Protocol respectively.

The second test message M2 contains a well-defined amount of nonzeropayload data. Preferably, the second test message M2 contains an amountof payload data that exceeds one maximum transmission unit (MTU) in theradio communications network NW. Namely, medium access control (MAC)techniques in the form of frame aggregation require such payload sizesin order to be engaged. If exclusively messages being shorter than orequal to one MTU were sent, the non-use of frame aggregation wouldresult in an overly optimistic estimate of the actual throughput for theradio communications network NW. In other words, a second test messageM2 of with an amount of payload data that exceeding one MTU provides abasis for studying the effects of frame aggregation in the network, sothat the network capacity can be estimated relatively accurately. InWiFi, the MTU size is 2304 bytes. This means that it is advantageous ifthe second test message M2 contains 2305 bytes or more. Preferably, thesecond test message M2 should contain at least 4608 bytes, so that threeor more separate packets must be generated.

The mobile radio network node UE is configured to perform acapacity-measuring step estimating the capacity of the link L in theradio communications network NW. The capacity is estimated based on:

-   -   (i) an amount of residue data corresponding to a difference        between the second and first amounts of data (i.e. the residue        data may be equal to the amount of payload data included in the        second test message M2 alone), and    -   (ii) a difference between first and second time intervals, where        the first time interval is the time elapsed between sending the        first test message M1 and receiving a first return message R1 in        response thereto, and the second time interval is the time        elapsed between sending the second test message M2 and receiving        a second return message R2 response thereto.

Here, it is presumed that both the return messages R1 and R2 have beengenerated by the end-point node EPN1.

Preferably, the mobile radio network node UE is configured to send thesecond test message M2 as soon after sending the first test message M1as is possible with respect to a communication protocol used in theradio communications network NW. Namely, thereby, the probability iscomparatively high that both messages M1 and M2 experience similar radioconditions. This, in turn, improves the quality of the capacityestimate.

According to one embodiment of the invention, the measuring stepspecifically determines an estimated average throughput via the link Lover a number of repeated measurements. To this aim, the mobile radionetwork node UE is preferably configured to determine the estimatedaverage throughput as:

$\frac{2\; D}{{{MSG}\; 2\; {RTT}_{AVG}} - {{MSG}\; 1\; {RTT}_{M\; {IN}}}}\mspace{14mu}\left\lbrack \text{amount of data/unit time} \right\rbrack$

-   where D is the amount of residue data,    -   MSG1RTT_(MIN) is a shortest round-trip time for the first test        message M1 and the first return message R1 over as many times as        the measurements have been repeated, and    -   MSG2RTT_(AVG) is an average round-trip time for the second test        message M2 and the second return message R2 over said number of        times.

The factor 2 in the numerator is included in the expression due to thefact that the return messages R1 and R2 are presumed to contain the sameamount of data as the corresponding test messages M1 and M2respectively.

Alternatively, or in addition to determining the estimated averagethroughput, the measuring step may determine an estimated maximumthroughput of the link L. To this aim, the mobile radio network node UEis preferably configured to determine the estimated maximum throughputas:

$\frac{2\; D}{{{MSG}\; 2\; {RTT}_{AVG}} - {{MSG}\; 1\; {RTT}_{M\; {IN}}}}\mspace{14mu}\left\lbrack \text{amount of data/unit time} \right\rbrack$

-   where D is the amount of residue data,    -   MSG1RTT_(MIN) is the shortest round-trip time for the first test        message M1 and the first return message R1 over as many times as        the measurements have been repeated, and    -   MSG2RTT_(MIN) is a shortest round-trip time for the second test        message M2 and the second return message R2 during said number        of times.

According to another embodiment of the invention, the mobile radionetwork node UE is specifically configured to repeat the measuring stepin such a manner that the second amount of data included in the secondtest message M2 is varied between different transmissions of the secondtest message M2 throughout the repeated measurements.

For instance, when estimating the capacity of a link L in the radiocommunications network NW, the following procedure can be applied:

-   1. Select an averaging window, i.e. a number of times specifying how    many repeated measurements that are to be performed. Consequently,    the averaging window size can be 10. However, of course, any other    larger or smaller integer number is equally well conceivable. The    averaging window size is preferably assigned as a global variable in    the settings of a computer program in the mobile radio network node    UE carrying out the proposed method.-   2. Select an end-point node EPN1. The mobile radio network node UE    is assumed to be one end-point of the link L, and EPN1 is assumed to    be the other. Preferably, the computer program in the mobile radio    network node UE is configured to perform a local network discovery    and present a list of available devices representing potential    end-point nodes. A user of the mobile radio network node UE may then    select the end-point node EPN1 from the list. Alternatively, the    user may identify the end-point node EPN1 by typing in a host name    or an IP address of the end-point node EPN1.-   3. Set sizes of the first and second test messages M1 and M2. As    mentioned above, the first test message M1 preferably contains no    payload data; and naturally, the larger the size of the second test    message M2, the more data will be sent in in each measurement cycle.    For high-speed networks a relatively large size of the second test    message M2 appropriate, say 64 Kbytes; whereas if for example the    link L passes over the Internet a smaller size of the second test    message M2 is suitable. In any case, an initial transmission of the    second test message M2 may contain a predefined maximum amount of    data. If no second return message R2 is received in response to the    second test message M2 (before a time-out timer expires), in at    least one transmission subsequent to the initial transmission, the    second test message M2 is generated such that this message contains    an amount of data being less than the predefined maximum amount of    data. For example, the size of the second test message M2 may be    stepwise reduced for each iteration measurement cycle.-   4. Simulated traffic is generated by (4a) sending a first test    message M1, (4b) receiving a first return message R1, (4c) sending a    second test message M2 and (4d) receiving a second return message R2    (provided that the time-out timer did not expire), and repeating    this procedure as many times as specified by the averaging window.-   5. Calculate average round trip times (RTT) for the simulated    traffic. In particular, this may involve calculating the    above-mentioned parameters MSG1RTT_(AVG) and MSG2RTT_(AVG). In    addition, the above-mentioned parameter MSG2RTT_(MIN) is determined,    if the estimated maximum throughput is to be presented.-   6. Calculate the estimated average throughput and/or the estimated    maximum throughput.

Finally, provided that both the estimated average throughput and theestimated maximum throughput are calculated, a network efficiency NE canbe determined as:

${{NE} = \frac{{THRUP}_{AVG}}{{THRUP}_{M\; {AX}}}},$

where THRUP_(AVG) is the estimated average throughput and THRUP_(MAX) isthe estimated maximum throughput.

It is generally advantageous if the estimated average throughputTHRUP_(AVG), the estimated maximum throughput THRUP_(MAX) and/or thenetwork efficiency NE is/are presented in “real time” while themeasurements are being executed. Further preferably, the parametersTHRUP_(AVG), THRUP_(MAX) and/or NE can be presented graphically, forexample in the form of a so-called heat map illustrating the capacity ofthe radio communications network in terms of amounts of datatransmittable per unit of time at respective positions on a map or aplan.

Such a heat-map representation is particularly well suited to illustratethe results of the measurements performed in an environment shown inFIG. 2. Here, we see a second embodiment of the invention, where themobile radio network node UE estimates the capacity of a link to asecond end-point node EPN2 in a radio communications network NW. Thesecond end-point node EPN2 is equipped with a radio interface configuredto communicate wirelessly directly with the mobile radio network nodeUE. Thus, the mobile radio network node UE may be repositioned whileestimating the capacity of a link L between the mobile radio networknode UE and the second end-point node EPN2. Thereby, any hotspots, radioshadows and/or other anomalies in a coverage area for the secondend-point node EPN2 can be identified and documented.

In a WiFi network the maximal attainable throughput is the highestpossible throughput for the mobile radio network node UE at a particularphysical location, and the average throughput is the actual throughputachieved by the mobile radio network node UE in this physical location.

High network efficiency NE indicates comparatively little competingtraffic on the channel, and relatively low jitter transmission, which isespecially important for low latency applications like VoIP (Voice overIP). Analogously, low network efficiency indicates a high channelutilization, which is typical for a highly trafficked network, and/or anetwork with high amounts of interference.

Due to the round-trip nature of the proposed solution, it may berelevant to present the capacity in a round-trip scenario. In general,the actual throughputs in an uplink and a downlink of the link L aredifferent. A weighted value THRUP_(L) may thus be determined as:

${{THRUP}_{L} = \frac{2 \cdot {THRUP}_{DL} \cdot {THRUP}_{UL}}{{THRUP}_{DL} + {THRUP}_{UL}}},$

-   where: THRUP_(UL) is an estimated throughput in the uplink, and    -   THRUP_(DL) is an estimated throughput in the downlink.

THRUP_(DL) 2 5 8 10 12 15 18 THRUP_(UL) 18 15 12 10 8 5 2 THRUP_(L) 3.67.5 9.6 10 9.6 7.5 3.6

-   -   Table exemplifying throughput values in Mbps, where a sum of        THRUP_(DL) and THRUP_(UL) is 20 Mbps in each case.

According to the invention, an amount of test traffic generated by eachtest cycle is caused by the two test messages M1 and M2 and thecorresponding return messages R1 and R2 respectively.

For example, in ICMP, the total amount of data sent, above the IP layer,will be two ICMP headers plus an amount of payload D times two. Theheader is 8 bytes and we assume that D is 64 KB. The maximal amount ofdata then becomes 2·(2·8+64 000)=128 032 bytes or 64 016 bytes perdirection. The decimal kilo-prefix is assumed. Provided that, a testcycle is performed once per second or less frequently, the overalltest-traffic throughput becomes approximately 1 Mbps in total, or 0.5Mbps each direction, which should be acceptable in most of today'snetworks.

As mentioned earlier, the capacity of low throughput networks ispreferably tested via lower payloads and/or with longer test cycleperiods to limit the overall test-traffic generated.

FIG. 3 shows a block diagram over a mobile radio network node UEaccording to one embodiment of the invention for use in a radiocommunications network NW to estimate the capacity of a link to adefined end-point node EPN1 or EPN2 in the network NW. In addition to aradio interface 340, the mobile radio network node UE includes aprocessor 310 and a memory 320. The memory 320 is a non-volatile datacarrier containing the computer program product 330 with instructions335 executable by the processor 310, whereby the mobile radio networknode UE is operative to effect the above-described measures.

In order to sum up, and with reference to the flow diagram in FIG. 4, wewill now describe a method according to one embodiment of the inventionfor a mobile radio network node UE for use in a radio communicationsnetwork NW to estimate the capacity of a link to a defined end-pointnode EPN1 or EPN2 in the network NW.

In a first step 410, the size of the second test message M2 is set. Step410 is optional. This means that if the second test message always has afixed size, step 410 is empty (i.e. involves no action). However, aswill be discussed below, it is advantageous if, in subsequent iterationsof the measuring steps, the size of the second test message M2 can beadjusted (e.g. be reduced stepwise).

Then, in a step 420, the first test message M1 is sent to the definedend-point node EPN1 or ENP2. The first test message M1 preferably has aminimal size. This is advantageous because it improves the chances ofobtaining a response with a relatively short delay; and more important,if no payload data is included in the first test message M1, it isstraightforward to calibrate the measurement with respect to overheaddata of the protocol.

A step 430 thereafter checks if a first return message R1 has beenreceived in response to the first test message M1. If so, a step 440follows; and otherwise, the procedure loops back and stays in step 430.

In step 440, the second test message M2 is sent to the defined end-pointnode, and subsequently a step 450 checks if a second return message R2has been received in response to the second test message M2. If so, astep 470 follows; and otherwise, the procedure continues to a step 460in which it is checked whether or not a time-out timer has expired. Ifthe time-out timer still runs, the procedure loops back to step 450; andotherwise, a step 480 follows.

In step 470, a capacity (typically in terms of amount of data per unittime, e.g. bits/s) is estimated based on the round-trip times for thefirst and second test messages M1 and M2 and the corresponding returnmessages R1 and R2 respectively. Then, step 480 follows in which it ischecked if a repeated measurement should be performed. For example, toobtain a relatively reliable estimate, the measurement may be performedten times. Thus, after having completed the first measurement, nineadditional iterations follow. Provided that at least one moremeasurement is to be performed, the procedure loops back to step 410.

As mentioned above, if the second test message M2 always has a fixedsize, step 410 is empty (i.e. involves no action). However, if, forinstance the time-out timer expired in step 460 in a previous iteration,step 410 preferably involves adjusting the size of the second testmessage M2 to contain a smaller amount of data

-   -   thus improving the chances of obtaining a second return message        R2 before the time-out timer expires.

If, in step 480 it is determined that no further measurements should beperformed, a step 490 follows. Here, the capacity of the capacity of thelink to the defined end-point node EPN1 or EPN2 is estimated, eitherbased on a single measurement, or based on an average over repeatedmeasurements. Thereafter, the procedure ends.

All of the process steps, as well as any sub-sequence of steps,described with reference to FIG. 4 above may be controlled by means ofat least one programmed processor. Moreover, although the embodiments ofthe invention described above with reference to the drawings compriseprocessor and processes performed in at least one processor, theinvention thus also extends to computer programs, particularly computerprograms on or in a carrier, adapted for putting the invention intopractice. The program may be in the form of source code, object code, acode intermediate source and object code such as in partially compiledform, or in any other form suitable for use in the implementation of theprocess according to the invention. The program may either be a part ofan operating system, or be a separate application. The carrier may beany entity or device capable of carrying the program. For example, thecarrier may comprise a storage medium, such as a Flash memory, a ROM(Read Only Memory), for example a DVD (Digital Video/Versatile Disk), aCD (Compact Disc) or a semiconductor ROM, an EPROM (ErasableProgrammable Read-Only Memory), an EEPROM (Electrically ErasableProgrammable Read-Only Memory), or a magnetic recording medium, forexample a floppy disc or hard disc. Further, the carrier may be atransmissible carrier such as an electrical or optical signal which maybe conveyed via electrical or optical cable or by radio or by othermeans. When the program is embodied in a signal which may be conveyeddirectly by a cable or other device or means, the carrier may beconstituted by such cable or device or means. Alternatively, the carriermay be an integrated circuit in which the program is embedded, theintegrated circuit being adapted for performing, or for use in theperformance of, the relevant processes.

The term “comprises/comprising” when used in this specification is takento specify the presence of stated features, integers, steps orcomponents. However, the term does not preclude the presence or additionof one or more additional features, integers, steps or components orgroups thereof.

The invention is not restricted to the described embodiments in thefigures, but may be varied freely within the scope of the claims.

1. A mobile radio network node (UE) for estimating the capacity of aradio communications network (NW), the mobile radio network node (UE)comprising: a radio interface configured to exchange data wirelessly viathe radio communications network (NW), a processor, and a memorycontaining instructions executable by the processor whereby the mobileradio network node (UE) is operative to: send echo request messages viaa link (L) in the radio communications network (NW) to a definedend-point node (EPN1, EPN2), and estimate the capacity of the link (L)in the radio communications network (NW) based on return messagesgenerated in response to the echo request messages, which returnmessages originate from the defined end-point node (EPN1, EPN2), whereinthe echo request messages comprise first and second test messages (M1;M2), where the first test message (M1) includes a first amount of data,and the second test message (M2) includes a second amount of dataexceeding the first amount of data, and the instructions executable bythe processor are further configured to render the mobile radio networknode (UE) operative to: perform a measuring step, wherein the capacityof the link (L) in the radio communications network (NW) is estimatedbased on (i) an amount of residue data corresponding to a differencebetween the second and first amounts of data, and (ii) a differencebetween first and second time intervals, where the first time intervalis the time elapsed between sending the first test message (M1) andreceiving a first return message (R1) in response thereto, and thesecond time interval is the time elapsed between sending the second testmessage (M2) and receiving a second return message (R2) responsethereto.
 2. The mobile radio network node (UE) according to claim 1,wherein the first and second amounts of data included in the first andsecond test messages respectively (M1; M2) are such that the residuedata comprises both payload data and overhead data generated by acommunication protocol used in the radio communications network (NW). 3.The mobile radio network node (UE) according to claim 2, wherein thefirst test message (M1) contains a minimal amount of payload data andthe second test message (M2) contains an amount of payload dataexceeding one maximum transmission unit in the radio communicationsnetwork (NW).
 4. The mobile radio network node (UE) according to claim2, wherein the instructions executable by the processor are furtherconfigured to render the mobile radio network node (UE) operative to:send the second test message (M2) as soon after sending the first testmessage (M1) as is possible with respect to a communication protocolused in the radio communications network (NW).
 5. The mobile radionetwork node (UE) according to claim 1, wherein the instructionsexecutable by the processor are further configured to render the mobileradio network node (UE) operative to: repeat the measuring step a numberof times, and perform an averaging operation over said number of timesto obtain the estimated capacity of the link (L) in the radiocommunications network (NW).
 6. The mobile radio network node (UE)according to claim 5, wherein the measuring step comprises at least oneof: determining an estimated average throughput, and determining anestimated maximum throughput.
 7. The mobile radio network node (UE)according to claim 6, wherein the instructions executable by theprocessor are configured to render the mobile radio network node (UE)operative to determine the estimated average throughput as:$\frac{2\; D}{{{MSG}\; 2\; {RTT}_{AVG}} - {{MSG}\; 1\; {RTT}_{M\; {IN}}}}\mspace{14mu}\left\lbrack \text{amount of data/unit time} \right\rbrack$and determine the estimated maximum throughput as:$\frac{2\; D}{{{MSG}\; 2\; {RTT}_{MIN}} - {{MSG}\; 1\; {RTT}_{M\; {IN}}}}\mspace{14mu}\left\lbrack \text{amount of data/unit time} \right\rbrack$where D is the amount of residue data, MSG1RTT_(MIN) is a shortestround-trip time for the first test message M1 and the first returnmessage R1 over said number of times, MSG2RTT_(AVG) is an averageround-trip time for the second test message M2 and the second returnmessage R2 over said number of times, and MSG2RTT_(MIN) is a shortestround-trip time for the second test message M2 and the second returnmessage R2 during said number of times.
 8. The mobile radio network node(UE) according to claim 5, wherein the instructions executable by theprocessor are configured to render the mobile radio network node (UE)operative to repeat the measuring step in such a manner that the secondamount of data included in the second test message (M2) is variedbetween different transmissions of the second test message (M2) oversaid number of times.
 9. The mobile radio network node (UE) according toclaim 8, wherein the instructions executable by the processor areconfigured to render the mobile radio network node (UE) operative to: inan initial transmission of said number of times, generate the secondtest message (M2) such that the second test message (M2) contains apredefined maximum amount of data; and if no second return message (R2)is received in response to the second test message (M2) in at least onetransmission subsequent to the initial transmission of said number oftimes, generate the second test message (M2) such that the second testmessage (M2) contains an amount of data being less than the predefinedmaximum amount of data.
 10. The mobile radio network node (UE) accordingto claim 1, wherein the radio communications network (NW) is configuredto communicate data according to at least one of: the Internet ControlMessage Protocol, ICMP; the Transmission Control Protocol, TCP; theReal-Time Transport Protocol, RTP; the User Datagram Protocol, UDP; andthe IETF RFC 862 Echo Protocol, and the instructions executable by theprocessor are con-figured to render the mobile radio network node (UE)operative to generate each of the first and second test messages (M1;M2) as a respective standardized message in ICMP, TCP RTP, UDP and IETFRFC 862 Echo Protocol respectively.
 11. A method performed in a mobileradio network node (UE) for estimating a capacity of a radiocommunications network (NW), the method comprising: sending echo requestmessages via a link (L) in the radio communications network (NW) to adefined end-point node (EPN1, EPN2), and estimating the capacity of thelink (L) in the radio communications network (NW) based on returnmessages generated in response to the echo request messages, whichreturn messages originate from the defined end-point node (EPN1, EPN2),wherein the echo request messages comprising first and second testmessages (M1; M2), where the first test message (M1) includes a firstamount of data, and the second test message (M2) includes a secondamount of data exceeding the first amount of data; and the methodcomprises: a measuring step, wherein the capacity of the link (L) in theradio communications network (NW) is estimated based on (i) an amount ofresidue data corresponding to a difference between the second and firstamounts of data, and (ii) a difference between first and second timeintervals, where the first time interval is the time elapsed betweensending the first test message (M1) and receiving a first return message(R1) in response thereto, and the second time interval is the timeelapsed between sending the second test message (M2) and receiving asecond return message (R2) response thereto.
 12. The method according toclaim 11, wherein the first and second amounts of data included in thefirst and second test messages respectively (M1; M2) are such that theresidue data comprises both payload data and overhead data generated bya communication protocol used in the radio communications network (NW).13. The method according to claim 12, wherein the first test message(M1) contains a minimal amount of payload data and the second testmessage (M2) contains an amount of payload data exceeding one maximumtransmission unit in the radio communications network (NW).
 14. Themethod according to claim 11, wherein the method involves sending thesecond test message (M2) as soon after sending the first test message(M1) as is possible with respect to a communication protocol used in theradio communications network (NW).
 15. The method according to any claim11, comprising: repeating the measuring step a number of times, andperforming an averaging operation over said number of times to obtainthe estimated capacity of the link (L) in the radio communicationsnetwork (NW).
 16. The method according to claim 15, wherein themeasuring step comprises at least one of: determining an estimatedaverage throughput, and determining an estimated maximum throughput. 17.The method according to claim 16, wherein the estimated averagethroughput is determined as:$\frac{2\; D}{{{MSG}\; 2\; {RTT}_{AVG}} - {{MSG}\; 1\; {RTT}_{M\; {IN}}}}\mspace{14mu}\left\lbrack \text{amount of data/unit time} \right\rbrack$and determine the estimated maximum throughput as:$\frac{2\; D}{{{MSG}\; 2\; {RTT}_{MIN}} - {{MSG}\; 1\; {RTT}_{M\; {IN}}}}\mspace{14mu}\left\lbrack \text{amount of data/unit time} \right\rbrack$where D is the amount of residue data, MSG1RTT_(MIN) is a shortestround-trip time for the first test message M1 and the first returnmessage R1 over said number of times, MSG2RTT_(AVG) is an averageround-trip time for the second test message M2 and the second returnmessage R2 over said number of times, and MSG2RTT_(MIN) is a shortestround-trip time for the second test message M2 and the second returnmessage R2 during said number of times.
 18. The method according toclaim 15, wherein the repeating of the measuring step involves varyingthe second amount of data included in the second test message (M2)between different transmissions of the second test message (M2) oversaid number of times.
 19. The method according to claim 18, wherein: inan initial transmission of said number of times, the second test message(M2) contains a predefined maximum amount of data; and if no secondreturn message (R2) is received in response to the second test message(M2) in at least one transmission subsequent to the initial transmissionof said number of times, the second test message (M2) contains an amountof data being less than the predefined maximum amount of data.
 20. Themethod according to claim 11, wherein the radio communications network(NW) is configured to communicate data according to at least one of: theInternet Control Message Protocol, ICMP; the Transmission ControlProtocol, TCP; the Real-Time Transport Protocol, RTP; the User DatagramProtocol, UDP; and the IETF RFC 862 Echo Protocol, and each of the firstand second test messages (M1; M2) and each of the first and secondreturn messages (R1; R2) is a standardized message in ICMP, TCP RTP, UDPand/or IETF RFC 862 Echo Protocol respectively.
 21. A computer programproduct embodied on a non-transitory computer-readable medium, thecomputer program product comprising instructions which, when executed onat least one processor, cause the at least one processor to carry out amethod performed in a mobile radio network node (UE) for estimating acapacity of a radio communications network (NW), the method comprising:sending echo request messages via a link (L) in the radio communicationsnetwork (NW) to a defined end-point node (EPN1, EPN2), and estimatingthe capacity of the link (L) in the radio communications network (NW)based on return messages generated in response to the echo requestmessages, which return messages originate from the defined end-pointnode (EPN1, EPN2), wherein the echo request messages comprising firstand second test messages (M1; M2), where the first test message (M1)includes a first amount of data, and the second test message (M2)includes a second amount of data exceeding the first amount of data; andthe method comprises: a measuring step, wherein the capacity of the link(L) in the radio communications network (NW) is estimated based on (i)an amount of residue data corresponding to a difference between thesecond and first amounts of data, and (ii) a difference between firstand second time intervals, where the first time interval is the timeelapsed between sending the first test message (M1) and receiving afirst return message (R1) in response thereto, and the second timeinterval is the time elapsed between sending the second test message(M2) and receiving a second return message (R2) response thereto. 22.(canceled)